exit

See also die. If EXPR is omitted, exits with 0
status. The only
universally recognized values for EXPR are 0
for success and 1
for error; other values are subject to interpretation depending on the
environment in which the Perl program is running. For example, exiting
69 (EX_UNAVAILABLE) from a sendmail incoming-mail filter will cause
the mailer to return the item undelivered, but that's not true everywhere.

Don't use exit to abort a subroutine if there's any chance that
someone might want to trap whatever error happened. Use die instead,
which can be trapped by an eval.

The exit() function does not always exit immediately. It calls any
defined END routines first, but these END routines may not
themselves abort the exit. Likewise any object destructors that need to
be called are called before the real exit. END routines and destructors
can change the exit status by modifying $?
. If this is a problem, you
can call POSIX::_exit($status)
to avoid END and destructor processing.
See perlmod for details.